Flow meters more measuring fluid flow rates through pipe lines are used in various industries. In-line flow meters employing paddlewheel-type rotors are among known flow meter types, and use the speed of driven rotation of the paddlewheel rotor by the passing fluid to calculate the rate at which the fluid is flowing through the pipe line at the location at which the flow meter is installed in series in between adjacent pipe sections. Some of these meters, prior art examples of which are listed below, employ T-shaped housings or pipe fittings, where a through-bore of the housing is coupled inline between two pipe sections, and a blind-bore perpendicular to the through-bore is used to house a support arrangement for the paddlewheel and an associated sensor for detecting the rotational speed of the paddlewheel.
Many commercially available flow meters are not suitable for use in harsh operating conditions, for example in the oilfield industry, where fluid lines being monitored may be subject to one or more extreme conditions, including high operating pressures, abrasive particulate matter (e.g. sand) carried in the fluid, and/or caustic chemical content. Some prior art flow meter designs include such features as paddlewheel rotors of plastic construction, which are eroded away under such operating conditions, and/or use of roller bearings, the seals of which may be prone to failure under high pressure conditions and/or abrasive conditions, thus leading to penetration of particulate into the bearing, causing wear that can lead to reduced rotational stability causing inaccurate flow readings, and eventual operational failure.
Another known issue is that many prior art designs have limited or non-existent on-site serviceability, whereby failure of any given internal component of the flow meter requires that the entire unit be removed from the pipeline for repair or replacement. Other prior art flow meters have allowed for some improvement by using removable installation of a support structure in the housing for carrying the paddlewheel and associate sensor, but require replacement of this entire internal working assembly, even if only one particular component thereof has failed or worn to a replacement-requiring level.
Accordingly, there remains room for improvement in the area of flow meters, and a particular desire for a paddlewheel flow meter with a high level of serviceability and a robust design providing reliability even in relatively harsh operating conditions.